MARTIN O'Neill is believed to be sizing up a summer swoop for Celtic's impressive Poland international Goalkeeper Artur Boruc.

I understand doubts surround the long-term future of Thomas Sorensen, not for his shot-stopping ability as was proved in the final minute of yesterday's goalless draw with Liverpool, but for his inability to dominate his area.

Watford's on loan England keeper Ben Foster could also come under the microscope Manchester United allow him out on loan again next season.

With O'Neill scanning the market Boruc has emerged as a potential candidate.

He moved to Celtic on what was originally a year-long loan from Polish team Legia Warsaw in July 2005 and after nine games the deal was made permanent in October of that year. He went on to keep hold of the number one jersey-playing 41 times, keeping 14 clean sheets - until David Marshall was given three games in the final month of the season, with the title already won.

Boruc played int he world Cup Finals and has established himself as his country's number one ahead of Jerzy Dudek.